The invention relates to a new, stable high-expansion aqueous foam formulation containing dibenz-(b,f)-1,4-oxazepine and stabilizers selected from glycerine, carboxyl vinyl polymers, and mixtures thereof.
The invention also relates to a method of obtaining visual obscuration and area denial in military operations through use of a novel, stable, high-expansion aqueous foam formulation containing dibenz-(b,f)-1,4-oxazepine in sufficient quantities to provide area denial for extended periods of time.
The invention further relates to an aqueous foam formulation which will remain stable even when stored for extended periods of time under severe environmental stress conditions.
The invention still further relates to an aqueous foam formulation containing dibenz-(b,f)-1,4-oxazepine as a deterrent which will adhere to the surface of objects or persons entering or moving about in a foam generated from the formulation.
The invention also relates to a foam formulation which can be used as a single composite solution or as two separate solutions to be mixed immediately prior to foam generation in conventional fire fighting foam generators.
Prior foam formulations have generally been adequate for achieving visual obscuration for short periods of time. Previous studies on foam formulations have used high expansion foams as carriers for selected deterrent chemicals such as military tear gas (CS), but these foams have exhibited inadequate foam stability in conjunction with a high liquid drainage rate. Only short-term effectiveness in visual obscuration and area denial have been achieved. An aqueous foam formulation containing ammonia developed by applicants and described in copending U.S. Pat. application, Ser. No. 886,961, filed Mar. 15, 1978, now U.S. Pat. No. 4,203,974 has succeeded in providing extended term stability of foam for both visual obscuration and area denial, but this requires the use of a relatively large amount of ammonia to achieve a deterrent effect which is less effective than the relatively small amounts of dibenz-(b,f)-1,4-oxazepine (CR) deterrent compound used in the present invention.